U.S. patent application number 13/959939 was filed with the patent office on 2013-12-05 for power drill.
This patent application is currently assigned to ROBERT BOSCH GMBH. The applicant listed for this patent is Tobias HERR, Heiko ROEHM. Invention is credited to Tobias HERR, Heiko ROEHM.
Application Number | 20130319707 13/959939 |
Document ID | / |
Family ID | 43567204 |
Filed Date | 2013-12-05 |
United States Patent
Application |
20130319707 |
Kind Code |
A1 |
ROEHM; Heiko ; et
al. |
December 5, 2013 |
POWER DRILL
Abstract
The invention relates to a power drill, having a tool-clamping
device that is fastened to a spindle shaft, having a torque clutch
that includes an axially movable clutch plate on which an axial
force is exerted by a plurality of compression springs that
cooperate at least indirectly with an adjusting nut situated on a
housing component. The compression springs are accommodated in
first recesses embodied in the longitudinal direction of the
housing component. A device for axially moving an axial bearing
situated on the spindle shaft, is provided at the end of the
spindle shaft oriented toward the tool-clamping device. According
to the invention, on its side oriented toward the clutch plate, the
device for axially moving the axial bearing has at least one
actuating section that is situated in a second recess of the
housing component and on the side oriented toward the clutch plate,
cooperates with an adjusting element for the device.
Inventors: |
ROEHM; Heiko; (Stuttgart,
DE) ; HERR; Tobias; (Stuttgart, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ROEHM; Heiko
HERR; Tobias |
Stuttgart
Stuttgart |
|
DE
DE |
|
|
Assignee: |
ROBERT BOSCH GMBH
Stuttgart
DE
|
Family ID: |
43567204 |
Appl. No.: |
13/959939 |
Filed: |
August 6, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12951725 |
Nov 22, 2010 |
8528658 |
|
|
13959939 |
|
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Current U.S.
Class: |
173/48 ;
173/47 |
Current CPC
Class: |
B25D 2250/165 20130101;
B25D 2250/205 20130101; B25D 2222/24 20130101; B25B 21/02 20130101;
B25D 2216/0023 20130101; B25D 2250/121 20130101; B25D 2216/0038
20130101; B25D 2222/21 20130101; B25D 2222/48 20130101; B25D
2250/065 20130101; B25D 2222/54 20130101; B25D 11/106 20130101;
B25D 16/003 20130101; B23B 31/1207 20130101; B23B 45/008
20130101 |
Class at
Publication: |
173/48 ;
173/47 |
International
Class: |
B23B 45/00 20060101
B23B045/00; B25B 21/02 20060101 B25B021/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 18, 2009 |
DE |
10 2009 054 930.7 |
Claims
1.-28. (canceled)
29. A power drill, comprising: a spindle shaft; a tool holder; a
torque clutch including an axially movable clutch member and at
least one spring member which exerts an axial force on the clutch
member; a first adjusting element configured to adjust the axial
force exerted by the at least one spring element on the clutch
member; wherein the first adjusting element has a root circle
diameter which is greater than an envelope curve of the at least
one spring member.
30. A power drill as defined in claim 29, wherein the first
adjusting element is arranged on a housing component.
31. A power drill as defined in claim 30, wherein the housing
component has at least one first recess in a longitudinal direction
of the housing component, the first recess being configured to
accommodate the at least one spring member.
32. A power drill as defined in claim 29, comprising an axial
bearing situated on and providing guidance for the spindle
shaft.
33. A power drill as defined in claim 32, comprising a device for
axially moving the axial bearing, said device having at least one
actuating member which is accommodated in at least one second
recess in a longitudinal direction of the housing component.
34. A power drill as defined in claim 33, wherein the at least one
actuating member are arranged radially inside the root circle
diameter of the adjusting element.
35. A power drill as defined in claim 33, wherein the device for
axially moving the axial bearing further comprises a first end
oriented towards the axial bearing.
36. A power drill as defined in claim 33, wherein the device for
axially moving the axial bearing further comprises a second end
oriented away from the axial bearing towards the clutch member.
37. A power drill as defined in claim 33, comprising a second
adjusting element configured to adjust the device for axially
moving the axial bearing such that the axial bearing is at least
one of a) movable during impact drilling of the power drill, and/or
b) fixed during screwdriving and/or drilling of the power
drill.
38. A power drill as defined in claim 37, wherein the second
adjusting element is configured to cooperate with the second end of
the device for axially moving the axial bearing.
39. A power drill as defined in claim 29, comprising a
spring-retaining element configured to retain the at least one
spring element, said spring-retaining element has a section that
protrudes radially inward.
40. A power drill as defined in claim 39, wherein the radially
inwardly protruding section has at least one pin-like extension for
guiding the at least one spring member thereon.
41. A power drill as defined in claim 39, wherein the first
adjusting element cooperates with the spring-retaining element to
adjust the axial force exerted by the at least one spring element
on the clutch member.
42. A power drill as defined in claim 39, wherein the
spring-retaining element has at least one support section
configured to rest against the clutch member for blocking movement
of the clutch plate in an axial direction during impact drilling of
the power drill.
43. A power drill as defined in claim 29, wherein the torque clutch
comprises at least one force-transmitting element, in particular
balls, said at least one force-transmitting element is arranged at
a radial distance from the spindle shaft which is substantially the
same radial distance of the at least one spring element from the
spindle shaft.
44. A power drill as defined in claim 43, wherein the number of
force-transmitting elements corresponds to the number of spring
elements and the force-transmitting elements are aligned with the
spring elements when the torque clutch is not slipping.
45. A power drill as defined in claim 29, wherein the tool holder
is embodied as a tool-clamping device that is fastened to the
spindle shaft.
46. A power drill as defined in claim 29, wherein the clutch member
is embodied as a clutch plate.
47. A power drill as defined in claim 29, wherein the at least one
spring member is embodied as a compression spring.
48. A power drill as defined in claim 29, wherein the at least one
actuating member is embodied as a strut-like actuating member.
49. A power drill as defined in claim 29, wherein a plurality of
strut-like actuating members are provided at equidistant angular
intervals from one another and each of the plurality of strut-like
actuating members are accommodated in one of a plurality of second
recesses in the housing component.
50. A power drill as defined in claim 29, wherein the housing
component is embodied as a transmission housing.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based on German Patent Application 10
2009 054 930.7 filed on Dec. 18, 2009.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a power drill.
[0004] 2. Description of the Prior Art
[0005] A power drill of this kind is already generally known. The
power drill has a torque clutch that makes it possible in
particular to also use the drill as a screwdriver. In this
operating mode, the torque clutch limits the torque transmitted to
the screw to a reasonable quantity. For this purpose, the known
power drill has a user-actuated adjusting ring that adjusts the
amount of torque that can be transmitted. This adjusting ring moves
an adjusting nut, which is situated on a transmission housing and
in particular, acts directly on axially situated compression
springs that in turn cooperate with an axially movable clutch
plate. In this case, the compression springs are guided between
threaded segments of the transmission housing on which the
adjusting nut is also situated.
[0006] In an impact drill, it is also known for the spindle shaft
bearing, which is situated at the end oriented toward a
tool-clamping unit, to move axially in the impact drilling mode so
that the bearing functions as a movable bearing, permitting an
impact mechanism to act on the spindle shaft. For this purpose, a
device is usually provided, which axially adjoins the torque
clutch.
OBJECT AND SUMMARY OF THE INVENTION
[0007] Based on the above-indicated prior art, the object
underlying the invention is to modify a power drill so that a
particularly compact axial design of the power drill is
achieved.
[0008] According to the invention, a device for axially moving the
bearing for the spindle shaft is positioned so that it at least
partially overlaps with the device for adjusting the torque of the
torque clutch. For this purpose, the device for moving the axial
bearing, on its side oriented toward the clutch plate, has at least
one actuating section that is situated in a second recess of the
housing component, which is particularly embodied as the
transmission housing, and on the side oriented toward the clutch
plate, cooperates with an adjusting element for the device for
moving the axial bearing. In other words, at least one actuating
section is situated in the region of the housing component in which
the compression springs are also situated.
[0009] According to an embodiment of the invention that is
particularly advantageous from a structural standpoint, the device
has a plurality of strut-like actuating sections that are situated
at equidistant angular intervals from one another and the second
recesses at least partially accommodate the strut-like actuating
sections in a form-locked fashion. This makes it possible to
transmit relatively high axial forces, with the guidance provided
for the actuating sections also guiding them laterally.
[0010] In order to accommodate the actuating sections so as to
achieve the axially short overall length, according to another
provided embodiment, the adjusting nut has a root circle diameter
that is greater than the envelope curve of the installed
compression springs and the strut-like actuating sections extend
radially inside the root circle diameter of the adjusting nut.
[0011] In order to transmit the axial force from the adjusting nut
to the compression springs, in a structural modification of the
invention, the adjusting nut cooperates with a spring-retaining
element that has a section, which protrudes radially inward and
cooperates with the compression springs.
[0012] In this case, in order to prevent the compression springs
from buckling laterally upon exertion of an axial force on the
compression springs, and to simultaneously achieve an optimum
frictional, nonpositive engagement between the compression springs
and the clutch plate, in another advantageous provided embodiment,
the inward-protruding section has pin-like extensions, each with a
respective compression spring guided on it, and the side of the
clutch plate oriented away from the spring-retaining element is
provided with force-transmitting means, in particular balls, whose
radial distance from the spindle shaft corresponds approximately to
the distance of the compression springs from the spindle shaft.
[0013] To immobilize the clutch device, particularly during impact
drilling mode, so as to enable a particularly good introduction of
force from the adjusting nut to the clutch plate, another
embodiment of the invention includes the provision that the
spring-retaining element has at least one support section that is
aligned with the adjusting nut in the axial direction and rests
against the clutch plate in order to immobilize the coupling plate
in the axial direction.
[0014] In order to minimize the number of components used and thus
to enable an optimum design of the power drill from a production
engineering standpoint, according to another advantageous
embodiment, the housing component is a transmission housing.
[0015] In this case, the transmission housing is relatively
convenient to produce from a production engineering standpoint if
it is embodied in the form of a pressure die-cast part composed of
metal (e.g. aluminum, magnesium, or zinc) or a pressure die-cast
part composed of plastic.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The invention will be better understood and further objects
and advantages thereof will become more apparent from the ensuing
detailed description of preferred embodiments taken in conjunction
with the drawings, in which:
[0017] FIG. 1 is a longitudinal section through the front part of a
power drill according to the invention in a first sectional
plane;
[0018] FIG. 2 is a longitudinal section through the front part of a
power drill according to the invention in a second different
sectional plane than in FIG. 1;
[0019] FIG. 3 is a perspective view of the front part of a
transmission housing;
[0020] FIG. 4 is a cross-section through the power drill according
to FIGS. 1 and 2, in the vicinity of the transmission housing;
and
[0021] FIG. 5 is a perspective depiction of the region of the front
transmission housing, with various parts not depicted for the sake
of clarity.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] FIGS. 1 and 2 show the axial front part of a power drill 10
according to the invention. The power drill 10 is in particular
embodied as a cordless drill and has an impact drilling function as
well as a screwdriving and drilling function. The power drill 10
has a tool-clamping device 11 that in a known way, includes in
particular three clamping jaws 12 arranged at equidistant angular
intervals from one another. The clamping jaws 12 can be opened and
closed in a known way in order to accommodate a suitable tool such
as a drill bit or screwdriving bit between the clamping jaws
12.
[0023] The tool-clamping device 11 is fastened to the end of a
spindle shaft 15 oriented toward it. The other end of the spindle
shaft 15 oriented away from the tool-clamping device 11 is
operatively connected to a clutch plate 17, with the clutch plate
17 situated in an axially movable fashion. The clutch plate 17 is a
component of a torque clutch 18, which has a plurality of balls 19,
preferably six of them, which are situated at equidistant angular
intervals from one another on the side of the clutch plate 17
oriented away from the tool-clamping device 11. The balls 19 are
operatively connected to a detent sleeve 21 that is connected to an
output gear of an in particular multi-stage transmission 20 of the
power drill 10, preferably embodied in the form of a planetary gear
set. The transmission 20 is in turn connected to the drive motor of
the power drill 10 (not shown).
[0024] The spindle shaft 15 is encompassed, with an interposed
bearing, by a clamping ring 22, which is in turn radially
encompassed by a transmission housing 24. For this purpose, the
transmission housing 24, as is particularly visible in FIGS. 1 and
2, has a recess 25 on the inside so that the transmission housing
24 can be connected to the clamping ring 22 by means of fastening
screws 26 that extend through the transmission housing 24 in
through bores. It should also be noted that the clutch plate 17 is
guided radially in the transmission housing 24.
[0025] The transmission housing 24 is in particular embodied in the
form of a pressure die-cast part composed of metal (e.g. aluminum,
magnesium, or zinc) or a pressure die-cast part composed of
plastic. As is depicted the most clearly in FIGS. 3 through 5, the
end of the transmission housing 24 oriented toward the
tool-clamping device 11 is provided with a threaded section 27 that
has three threaded struts 28 situated at equidistant angular
intervals from one another. The threaded struts 28 with their
external thread 29 serve to fasten and axially guide an adjusting
nut 30 (see FIGS. 1, 2, and 4). The adjusting nut 30 is likewise a
component of the torque clutch 18; it cooperates with an adjusting
ring 32 and can be actuated by means of it. As is depicted most
clearly in FIGS. 3 through 5, the transmission housing 24 has first
recesses 33 extending in the longitudinal direction of the
transmission housing 24, in which a number of compression springs
35 in particular corresponding to the number of balls 19, i.e. six
compression springs 35 in the exemplary embodiment, are situated at
equidistant angular intervals from one another. The compression
springs 35 and the balls 19 are advantageously arranged so that
they are aligned with one another when the detent sleeve 21 of the
torque clutch 18 is not slipping. In this case, viewed in the
radial direction, the compression springs 35 all extend inside the
root circle of the external thread 29 of the transmission housing
24 and are spaced apart from the spindle shaft 15 by approximately
the same radial distance as the balls 19. The one end of each
compression spring 35 acts on the clutch plate 17. An axial force
is exerted on the compression springs 35 by means of a
spring-retaining element 37 that is coupled to the adjusting nut
30. For this purpose, the spring-retaining element 37, as shown in
FIG. 1, has a section 38 protruding radially inward, which has a
pin-like extension 39 for each compression spring 35. Each
extension 39 accommodates and guides a respective compression
spring 35. Aligned with the adjusting nut 30, the spring-retaining
element 37 also preferably has a plurality of support regions 41
situated at equidistant angular intervals from one another, which
extend parallel to the extensions 39 and rest against the clutch
plate 17 when the clutch plate 17 is in an immobilized
position.
[0026] In addition to the first recesses 33, the transmission
housing 24 has second recesses 43. The second recesses 43, which
are depicted most clearly in FIGS. 3 and 4, are likewise situated
at equidistant angular intervals from one another in the
transmission housing 24 and in particular, are embodied as
groove-shaped. The second recesses 43 serve to at least partially
accommodate strut-like actuating sections 44 in a form-locked
fashion.
[0027] The actuating sections 44 are components of a bearing holder
45 (FIGS. 1 and 2) that is provided to axially move an axial
bearing 47. The axial bearing 47 in this case is situated at--and
provides guidance for--the end of the spindle shaft 15 oriented
toward the tool-clamping device 11. The ends of the actuating
sections 44 oriented away from the axial bearing 47 rest against a
cam ring 48 that functions as an adjusting element and is likewise
coupled to the adjusting ring 32, particularly in a form-locked
fashion. In this case, the cam ring 48 is used to axially move the
actuating sections 44 and bearing holder 45 so that the axial
bearing 47 functions as a movable bearing for the impact drilling
mode of the power drill 10 and functions as a fixed bearing for the
screwdriving and drilling modes.
[0028] In drilling mode, as shown in FIG. 5, the bearing holder 45
rests with its actuating sections 44 axially against the
transmission housing 24 via the cam ring 48; for this purpose, the
clutch plate 17 has recesses 49 so that spacer elements 50 formed
onto the cam ring 48 can cooperate with the transmission housing
24. In order to increase the transmittable torque, the adjusting
ring 32 is rotated so that the adjusting nut 30 is moved axially in
the direction of the clutch plate 17. As a result, the compression
springs 35 exert an increased axial compressive force against the
clutch plate 17 via the spring-retaining element 37.
[0029] In the drilling mode of the power drill 10, the support
regions 41 and/or the extensions 39 in turn press the clutch plate
17 until it is virtually locked in place, thus immobilizing the
torque clutch 18.
[0030] The foregoing relates to preferred exemplary embodiments of
the invention, it being understood that other variants and
embodiments thereof are possible within the spirit and scope of the
invention, the latter being defined by the appended claims.
* * * * *